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local m = require'lpeglabel'
local re = require'relabel'
local terror = {
ErrId = "expecting an identifier",
ErrComma = "expecting ','",
ErrList = "expecting a list of identifiers",
fail = "undefined"
}
local subject, errors
function recorderror(pos, lab)
local line, col = re.calcline(subject, pos)
table.insert(errors, { line = line, col = col, msg = terror[lab] })
end
function record (lab)
return (m.Cp() * m.Cc(lab)) / recorderror
end
function sync (p)
return (-p * m.P(1))^0
end
function defaultValue ()
return m.Cc"NONE"
end
local id = m.R'az'^1
local g = m.P{
"S",
S = m.V"List" + (m.P(1) * m.T'ErrList'),
List = m.V'Id' * (#m.P(1) * m.V'Comma' * (m.V'Id' + m.T'ErrId'))^0,
Id = m.V'Sp' * m.C(id),
Comma = m.V'Sp' * ',' + m.T'ErrComma',
Sp = m.S' \n\t'^0,
ErrId = record'ErrId' * sync(m.P",") * defaultValue(),
ErrComma = record'ErrComma' * sync(id),
ErrList = record'ErrList' * sync(m.P(-1)) * defaultValue()
}
function mymatch (g, s)
errors = {}
subject = s
io.write("Input: ", s, "\n")
local r = { g:match(s) }
io.write("Captures (separated by ';'): ")
for k, v in pairs(r) do
io.write(v .. "; ")
end
io.write("\nSyntactic errors found: " .. #errors)
if #errors > 0 then
io.write("\n")
local out = {}
for i, err in ipairs(errors) do
local msg = "Error at line " .. err.line .. " (col " .. err.col .. "): " .. err.msg
table.insert(out, msg)
end
io.write(table.concat(out, "\n"))
end
print("\n")
return r
end
mymatch(g, "one,two")
mymatch(g, "one two three")
mymatch(g, "1,\n two, \n3,")
mymatch(g, "one\n two123, \nthree,")
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